SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2db13b491bc15633972352b9899a95d658511bc699c4c602503121a2196837f3' 
  AND token = 'XLkSnK566Lhaw2gGednxX0HLdEcP4MNOVR32kiL6DhQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}